The invention relates to an airbag device for protecting a front seat passenger, disposed on an instrument panel in front of the passenger.
Conventionally, an airbag device for front seat passengers comprises an airbag, an inflator, and a casing (reference should be made to Japanese Patent Laid-Open No. 268602/1999). The airbag is folded when put in the casing, the inflator supplies expansion gas to the airbag, and the casing receives and holds both the airbag and the inflator.
The airbag is provided with an opening for inflowing gas to inflate and deploy the airbag. A retainer is used for mounting the airbag to the casing. The retainer compresses a peripheral edge of the opening through which the gas will flow and is mounted to a seat on the casing. The retainer is provided with a plurality of bolts that pass through the peripheral edge of the opening for the inflowing gas and the mounting seat of the casing, and are clamped by nuts. As a result, the retainer is mounted to the casing.
Also, the inflator includes a flange at one end thereof and an axially extending male thread portion at the other end. The inflator is mounted to the casing by inserting the inflator into the casing with the male thread portion going through the casing in the forefront from the other side (insertion side) so that the male thread portion projects from one side (the projecting side) of a lower part of the casing. The projecting male thread portion permits a nut to be clamped on the male thread portion on the projecting side surface. This causes the flange of the inflator to abut tightly against an outer surface of the insertion side of the casing. More specifically, the inflator is mounted to the casing in such a manner that the nut and the flange of the inflator interpose therebetween both sides (the projecting side and the insertion side) of the lower portion of the casing.
As described above, with the conventional airbag device for a front seat passenger, it has been necessary to mount the retainer to the casing when the airbag is to be mounted to the casing. Also, when the inflator is to be mounted to the casing, it has been necessary to clamp the nut on the male thread portion of the inflator. Therefore, assembly and installation of conventional airbag devices for passengers, has required extensive assembly and installation effort and utilized a relatively large number of constituent parts.
It is an object of the invention to solve the above-mentioned problems and to provide a passenger airbag device, which has fewer constituent parts and is easily assembled and installed.
The above-mentioned objective can be attained by an airbag, an inflator, a casing and a retainer that are uniquely held together. The airbag is provided with an opening for admitting expansion gas and is capable of being folded down so as to be positioned within the casing. The inflator has a cylindrical configuration and is capable of supplying the expansion gas to the airbag. The casing accommodates both the folded airbag and the inflator. The retainer compresses a peripheral edge about an opening of the airbag and is mounted to the casing thereby securing the airbag to the casing. Further, the retainer is provided with inflator presser portions, that press against the inflator when the retainer is mounted to the casing. The casing is itself provided with supports at opposite ends thereof, that support the inflator when the inflator is positioned therein. The inflator is securely held at each end thereof by respective inflator presser portions and supports when mounted within the casing.